A new method for tear film stability analysis using videokeratography

PURPOSE: To report a new tear film stability analysis system using videokeratography. DESIGN: Observational case series. METHODS: New videokeratography software for TMS-2N (topographic modeling system; TOMEY Cor, poration, Nagoya, Japan) was developed that can auto. matically capture consecutive corneal surface images every second for 10 seconds. Forty-eight adult volunteers (80 eyes) were recruited for this study, and all subjects were examined with the new system. Corneal topographs were analyzed for tear breakup time (TMS BUT) and the ratio of breakup area to entire color-code area (TMS. BUA) was calculated. Routine methods for tear film breakup time evaluation using slit,lamp microscope and fluorescence staining (SLE-BUT) were performed for comparison purposes. Regressive correlations of TMS-BUT or TMS-BUA with SLE-BUT were analyzed. Based on SLE results, subjects were separated into two groups with normal and short BUT, respectively. TMS BUT and TMS,BUA were compared with SLE-BUT data with regard to the sensitivity and specificity of evaluation of dry eye symptoms. RESULTS: Topographic modeling system-tear breakup time (TMS-BUT) had a positive correlation with SLE-BUT (R = 0.7219, P < .0001), whereas TMS-BUA showed a negative correlation (R = 0.6317, P < .0001). Among 34 eyes with normal SLE,BUT, 11 eyes (32.35%) displayed abnormal TMS-BUT, 9 (81.82%) of which were associated with dry eye symptoms. The sensitivities of TMS,BUT and TMS-BUA were 97.5% and 95%, respectively, significantly higher than that of SLE-BUT (75%), with P = .008 and 0.01, respectively. Topographic modeling, system-BUT and TMS-BUA displayed a similar rate of specificity in comparison with SLE-BUT. CONCLUSIONS: This new videokeratography system is noninvasive and objective method with increased sensitivity for tear film stability I analysis. (C) 2003 by Elsevier Inc. All rights reserved.)